Device for injecting fluid for medical use

ABSTRACT

The invention relates to a device for injecting a fluid for medical use and is characterized in that the device consists of a base wherein a container ( 2 ) for receiving the injection fluid is provided, said container being formed by a bellows-shaped body ( 6 ) made of deformable material and including a top surface ( 4 ) comprising a tip ( 7 ) through which fluid passes, while the base ( 1 ) consists of a bottom wall, enabling the axially translatable piston rod to be guided, and a top wall, characterized in that:—the tip ( 7 ) is inserted into a suitable arrangement of the lop wall of the base,—the top surface ( 4 ) and the bottom wall are conical in shape, while the chamber ( 6 ) of the container ( 2 ) consists of circular rings, and the piston has a shape complementing the shape of the cavity ( 8 ) of the bottom wall ( 5 ) such that, when the bellows is completely folded up into itself after injection, the chamber is totally empty, with no residual liquid.

The invention relates to a device for injecting fluid for medical use,intended for the human or animal body.

Current medicine uses various types of injections to dispense asubstance into the body of patients for various purposes, such astransfusions or artificial feeding methods, for example, in particularthrough the blood or the digestive tract (parenteral or enteralnutrition). Methods for analyzing and monitoring the state of patientsalso use injections of contrast agents. This is the case, for example,of studies such as angiography, for which an iodized substance isinjected in the vessels, veins and arteries to opacify them, as well asthe irrigated tissues and organs, in order to detect possibleabnormalities using radiography. Injections of iodized contrast agentsare also used to perform a conventional or digital scan or angiography,the intravenous or arterial injection being carried out in the form of abolus injection, typically at a rate of 0.5 to 35 mL/s.

Nuclear magnetic resonance imaging (MRI) tests also require injecting acontrast agent, such as Gadolinium, for example.

Various injection devices are known, which are generally comprised of aninjector containing the substance to be injected and actuated by anelectromechanical or a hydraulic mechanism. The injectors used, forexample, have a flexible pouch in which the substance is packageddirectly in flexible envelopes. These envelopes are then arranged in asealed enclosure of the injection device under pressure.

Syringe-type injectors are also used, in which the substance is packagedin the barrel of the syringe, which includes a manually or mechanicallyactuated movable piston, due to an injection device whose mechanismactuates the piston in axial translation.

Injectors with a flexible bag have the advantage of being capable ofbeing pre-filled with the substance to be injected, which makes themeasier to handle and improves asepsis. However, since ejection of thesubstance requires a pressurizing chamber, this increases the size andweight of the injection devices and lengthens their handling.

Syringe injectors are easier to use but have the disadvantage of beingcapable of being filled only at the time of use. As a result, handlingthese injectors, prior to being fitted in the injection device, is moretime-consuming and especially presents a greater risk of contamination.

The object of the invention is therefore to propose an injector whichcombines the advantages of the two aforementioned types, without havingtheir disadvantages.

To this end, the object of the present invention is a device forinjecting a fluid for medical use, comprising a sleeve in which acontainer for receiving the fluid to be injected is arranged, suchcontainer being comprised of an axially deformable body, of a topsurface provided with a tip engaged in a suitable arrangement at the topof the sleeve, for passage of the fluid, and of a bottom surface takingsupport on a piston movable in axial translation in the sleeve.

The container of the invention is therefore a deformable syringe withoutpiston, since its deformation from a deployed position to a collapsedposition occurs due to the deformation of its wall, which is comprisedof a succession of deformable circular rings capable of collapsing onthemselves.

According to other advantageous characteristics of the invention:

-   -   The inner wall of the top of the sleeve and the outer wall of        the top surface of the container have complementary shapes.    -   Similarly, the outer wall of the bottom of the container and the        piston have complementary shapes.    -   Preferably, the top surface and the bottom of the container have        a conical shape that is adjusted to enable said bottom to be        nested in the top surface at the end of the axial translational        movement of the piston.    -   The volume generated by the conical surface of the bottom of the        container forms a hollow outer housing into which the        complementary shape of the piston gets nested.    -   The bottom of the container comprises a stud in its center,        which is axially aligned with the tip borne by the top surface        and whose diameter, except for the functional clearance, is        substantially equal to the inner diameter of the tip. As a        result of this complementary geometry, there is zero residual        volume at the end of the injection.    -   The sleeve comprises a window through which the container        passes, and its top is provided with a notch that opens out in        the window, on the one hand, and in a central opening of the        top, which is suitably sized to receive and retain the tip of        the container, on the other hand.    -   The wall of the container body is in the form of a bellows whose        profile enables it to collapse during compression.    -   In an alternative embodiment, the wall of the container body is        formed of a bellows having circular rings.    -   Advantageously, the lateral rigidity of the structure of the        container is adjusted to prevent any parasitic elasticity.    -   The geometry of the bellows is such that deformations other than        those generated by the axial translation are quasi nonexistent.    -   To enable the container to be filled, the piston is provided        with a device that enables it to be affixed to the bottom of        said container, when the latter is empty, and it is actuated by        an axial translational tractive movement of the latter.    -   In an embodiment, the sleeve can be doubled so as to receive a        plurality of containers, each of the containers being controlled        independently.

Other characteristics and advantages of the invention will becomeclearly apparent upon reading the description that follows, given by wayan example, with reference to the annexed drawings, in which:

FIG. 1 is a perspective cross-sectional view of the container accordingto the invention, in the deployed position;

FIG. 2 is perspective cross-sectional view of the same container in thecollapsed position;

FIGS. 3 and 4 are views similar to the preceding Figures but accordingto external view without tear-out;

FIG. 5 is a perspective view of the injection device being used;

FIG. 6 is a perspective view of the injection device, at the end of theinjection, the container being in the completely collapsed position;

FIG. 7 is a view of the injection device showing the handling of thecontainer; and

FIG. 8 is a detailed view of an improvement.

The injection device according to the invention is comprised (FIG. 5) ofa support (1) which, according to the embodiment illustrated, is agenerally cylindrical sleeve carrying a container (2) adapted to receivethe fluid to be injected. The support (1) includes a piston (3) movablein axial translation.

The container (2) is deformable and is made of a deformable materialsuch as plastic, for example polypropylene, enabling it to be pre-filledwith the fluid to be injected.

This container (2) forms a volume whose wall is axially deformable. Tothis end, the wall is comprised of a top portion (4) and a bottomportion (5), both having the shape of a cone. The peripheral wallforming the body of the enclosure (6) has the shape of a deformablebellows having circular rings (21) such that, when the bellows iscompletely collapsed on itself, the container is completely empty, withno residual liquid. Thus, the wall of the bellows-shaped container iscomprised of a succession of circular rings whose periphery has atriangular cross-section, each of the rings thus including a top surface(210) that is conical upward and a bottom surface (211) that is conicaldownward. It is noted that in the collapsed position, each top surface(210) is in contact with the bottom surface (211) of the adjacent ring.

It is noted that the top surface (4) of the container, in its center,carries a cylindrical tip (7) through which the fluid contained in saidcontainer passes.

The volume generated by the conical surface of the bottom (5) is outsideof the volume of the container and thus forms a hollow housing (8). Itis noted that the bottom (5), in its center, comprises a centering stud(9) axially aligned with the tip (7), and whose diameter, except for thefreedom of axial clearance, is substantially equal to the inner diameterof the tip so that, in the collapsed position, said stud is engaged inthe tip, as is illustrated in FIG. 2.

The support (1) comprises an adequately sized lateral opening (10)forming a window to enable the passage and positioning of the container(2), as illustrated in FIG. 5. According to the embodiment shown, thesupport is a sleeve closed in its upper portion by a top (11) having theshape of a spherical cap on the outside, and the inner walls of whichform a conical surface whose shape is complementary to the outer wall ofthe top portion (4) of the container.

The top (11) comprises a radial notch (12) that opens out in the window(10), on the one hand, and in a central opening (13) of the top, on theother hand.

A piston (3) affixed to one end of a pin (15) is housed in the sleeve(1), such pin extending through the base (16) of the sleeve in order tobe connected via its second end to an actuation mechanism capable ofgenerating an axial translational movement F transmitted by the pin (15)to the piston (3).

According to a preferred embodiment of the invention, the outer shape ofthe piston is complementary to that of the surface opposite the housing(8) formed in the bottom (5) of the container.

It is noted that the support (1), which has the shape of a sleeveaccording to the illustrations proposed by way of an example, could haveany other shape. Thus, it may not have a peripheral wall, and thus becomprised of a stirrup including an upper wall forming the top (11)connected to a lower wall forming the base (16) by one or moreconnecting arms, or even any other connection.

The method for positioning the container in the support (1) is easilyunderstood from the preceding description. The container (2) containingthe medical fluid is inserted therein, through the window (10) along atransverse translational movement. In this step, the piston (3) is inthe low position in which it rests on the base (16) of the support.

The tip (7) of the container, provided with a nozzle (17) attached tothe tip by means of a connection (18), is inserted via the notch (12)into the opening (13) of the cap (11). Blocking means (not shown),adapted to prevent the container from pivoting about its axis, can beprovided.

The piston (3) and the hollow housing (8) of the bottom (5) of thecontainer (2), having complementary shapes, nest completely one into theother, thus blocking the transverse displacement of the latter.

When the actuating mechanism exerts a translational movement along (F)on the pin (15) of the piston, along the longitudinal axis, said pistonmoves in the same direction by exerting a compressive force on thecontainer, which generates the contraction, and therefore the collapsingand contraction of the deformable wall (6) of the container and, at thesame time, the backflow of the fluid contained therein.

It is noted that the complementarity of the shape of the piston and ofthe bottom of the container enables a uniform collapsing of the body ofthe container, the collapsing rings (19) nesting in one another, as isillustrated in FIGS. 2 and 4.

When the ejection of the fluid is complete, and the container iscompletely contracted, the bottom (5) and top surface (4) of thecontainer are in contact with one another, and its stud (9) is engagedin the tip (7) in order not to leave any quantity of residual fluid. Infact, the amount of residual fluid is close to zero, due to the adaptedshape of each of the co-operating elements, which makes it possible toobtain completely jointed collapsing rings 19 at the end of thetranslational movement.

The empty container is then removed from the sleeve along atranslational movement opposite that which enabled its insertiontherein.

It is noted that the conical shape of the container prevents airbubbles, which can form when it is being filled, from sticking to itswalls. These air bubbles are thus located at the top and are evacuatedfirst during the bubble removal operation.

It is noted that the lateral rigidity of the structure of the containeris adjusted to avoid any parasitic elasticity within the limit of normalpressures for this type of equipment (21 bars, 300 psi) and that thecontainer is tightly retained in its sleeve, with the exception of theaxial displacement clearance.

Indeed, the thrust exerted on the container by the piston must generatea continuous forward movement. To this end, the deformation of thecontainer must be exerted only in the axial direction, i.e., in thedirection of the force F generated by the piston in order to control theinstantaneous volume and, consequently, the ejection rate and pressureof the fluid contained in said container.

The mechanism for actuating the piston is selected suitably to generatea continuous and adjustable translational movement, such as a hydrauliccylinder or an electric motor, with brushless electronic control, forexample.

The container, once emptied, can be filled again. To this end, thesleeve that has just been described, or a similar sleeve, is used. Thecontainer is in the position shown in FIG. 6, in which it is pressedflat against the inner wall of the top (11) of the sleeve, its tip (7)being retained in the opening (13) of the top.

The piston is provided with a device enabling it to be affixed to thebottom of the container, and its actuation mechanism exerts an axialtranslational movement on it, in the opposite direction in relation tothe preceding direction (F). The bottom (5) of the container is providedwith a means for fastening to the piston (3), thus enabling the fillingby suction in the same manner as a conventional piston syringe. Thebottom (5) of the container is driven towards the base of the sleeve bythe piston, so that the container gradually reassumes its initial shapewhile sucking the liquid.

It is further noted that the sleeve can be adapted so as to receive aplurality of containers, each of the containers being controlledindependently (a plurality of sleeves).

The injection device that has just been described makes it possible,with the same injection system, either to use containers that have beenprefilled with the fluid to be injected, or to fill up the containers atthe time of use.

It is therefore particularly flexible and versatile. Moreover, itsarrangement and its injection system are simple, and it does not requirea power generator that is penalizing in terms of cost and spacerequirement.

FIG. 8 is a detailed view of an improvement according to which the tip(7) includes a stopper (70) equipped with a cover (71), whereas, duringconnection to the injection tube (72), a projection (73) of theconnector (74) perforates the cover (71).

It is understood that when the container (2) is completely compressed atthe end of the injection, the rings forming the bellows are jointed viatight nesting, so that there is no residual medical liquid left.

It is also understood that the bottom wall (16) is used to guide thepiston rod, whereas the top wall (11) is used to support the enclosure(2).

1. Device for injecting a fluid for medical use, characterized in thatit is comprised of a support (1) in which a container (2) for receivingthe fluid to be injected is arranged, said container being formed of abody (6) made a of deformable material, having the shape of a bellows inorder to be capable of being axially compressed and including a topsurface (4) comprising a tip (7) through which the fluid passes, whereasthe support (1) is comprised of a bottom wall (16) enabling the guidingof the rod of a piston (3) movable in axial translation, and of a topwall (11), characterized in that the tip (7) is engaged in a suitablearrangement (12), (13) of the top wall (11) of the support, the topsurface (4) and the bottom wall (16) have the shape of a cone, whereasthe enclosure (6) of the container (2) is comprised of circular rings,and the shape of the piston (3) is complementary to the shape of thehousing (8) of the bottom wall (5), such that when the bellows iscompletely collapsed on itself after injection, the enclosure is empty,with no residual liquid.
 2. Injection device according to claim 1,characterized in that the wall of the container is comprised of asuccession of circular rings whose periphery is triangular incross-section, each of the rings thus including a top surface (210) thatis conical upward and a bottom surface (211) that is conical downward,so that, in the collapsed position, each top surface (210) is in contactwith the bottom surface (211) of the adjacent ring.
 3. Injection deviceaccording to claim 2, characterized in that the enclosure (2) is madeout of a plastic material.
 4. Injection device according to claim 3,characterized in that the bottom (5) comprises, in its center, a stud(9) that is axially aligned with the tip (7) carried by the top surface(4), and whose diameter, except for the axial clearance, issubstantially equal to the inner diameter of the tip.
 5. Injectiondevice according to claim 1, characterized in that the support (1)comprises a window (10) through which the container passes, and in thatits top (11) is provided with a notch (12) that opens out in the window(10), on the one hand, and in a central opening (13) of the top, whichis suitably sized to receive and retain the tip (7) of the container, onthe other hand.
 6. Injection device according to claim 1, characterizedin that the piston (3) is provided with a device enabling it to beaffixed to the bottom (5) of the container, when the latter is empty,and in that it is actuated by of an axial translational tractivemovement of the latter.
 7. Injection device according to claim 1,characterized in that the support is adapted so as to receive aplurality of containers, each container being controlled independently.8. Injection device according to claim 1, characterized in that thecontainers ready for use, whether empty or full, are equipped with apierceable tip guaranteeing the sterility of the unit.